Western Digital manufactures the Passport line of portable external hard drives. If you originally used a Passport drive with an Apple computer, you most likely formatted it in the Mac OS Extended format, which is not compatible with the Windows operating system. To switch a Passport from Mac to PC so that it can be used with Windows workstations within your business, you must reformat the hard drive. Make sure to copy all of the drive's data to another location before formatting, because none of the Mac's data will carry over after the drive has been formatted.

1. Connect the WD Passport's USB cable to your PC.

2. Click "Start," right-click "Computer" and choose "Manage."

3. Expand the "Storage" directory on the left side of the window, then highlight "Disk Management."

4. Select the Passport from the list of drives, right-click on the black bar underneath it and choose "New Simple Volume."

5. Click "Next" in the popup window that appears.

6. Enter the maximum amount of disk space in the "Simple volume size in MB" field, then click "Next."

7. Choose which drive letter you want to assign to the Passport and click "Next" again.

8. Set the "File system" type to "NTFS" and enter a name for the Passport in the "Volume label" field. Check the box next to "Perform a Quick Format" and click "Next."